1. Field of the Invention
The present invention relates to an air bag system for a vehicle, particularly to an air bag system for a vehicle, which unfolds and expands an air bag downward from an upper portion of each side window of a vehicle body in a curtain manner, so as to protect an occupant when a side impact is applied onto the vehicle.
2. Description of the Related Art
As disclosed in U.S. Pat. No. 5,921,575, an air bag system for a vehicle has been known, which unfolds and expands an air bag in a curtain manner over a side face of the vehicle interior, serving as a passenger protection system to protect an occupant's head when the vehicle undergoes a side impact or roll-over accident.
Such an air bag system for a vehicle that is disclosed in U.S. Pat. No. 5,921,575, is an occupant protection system, so-called as a curtain air bag system, which is extendedly provided from a front pillar via a roof side rail to a rear pillar. In such an air bag system for a vehicle, the air bag in a normal condition is housed in a folded state in a long (container-like) cover that is disposed in a space between a roof lining as an interior member for the vehicle interior and an inner member as part of the vehicle body.
The cover is formed like a long container that is disposed in the above-mentioned space along the roof lining in such a manner to downwardly face toward the vehicle exterior side. The cover is formed to be long and approximately straight in the longitudinal direction of the vehicle body, and the air bag is folded and housed in the cover, whose open end is closed with a cover member being clipped at an edge of the open end.
The air bag expands with gas supplied from an inflator when an impact is applied, so that the bag pushes and breaks the cover member at the open end of the cover, and pushes down the roof lining at its lower end towards the vehicle interior side, so as to open up the roof lining and expands towards the vehicle interior to protect an occupant or occupants.
In addition, another air bag system for a vehicle with a rolled air bag, disclosed in JP 2006-88846 A, is disposed extendedly between a front pillar and a roof side rail, and unfolds and expands the air bag downwards by gas injection from an inflator when an impact is applied onto the vehicle, so as to protect an occupant or occupants. FIG. 8 shows a diagram of this conventional air bag system as a prior art.
As shown in FIG. 8, the air bag system A houses a rolled air bag 330 in a cover 310, and is installed to the vehicle body in such a manner that a clip (also referred to as a “locking portion”) 360 is inserted through a lock hole 300a of the roof side rail 300.
This air bag system A can be easily installed simply by pushing the cover 310 onto the roof side rail 300, resulting in reduction of time for installation of the system.
However, when such a conventional air bag system for a vehicle, as disclosed in U.S. Pat. No. 5,921,575, is disposed inside the roof lining, it is necessary to form the cover in such a manner as to be bent to avoid frame members such as a center pillar and other body frames of the vehicle body, in the light of the limited space. Therefore, it is necessary for a cover housing an air bag to be formed three-dimensionally, so as to go along the face shape of the vehicle body where the cover is installed.
In such a case, there has been a disadvantage that, at a bent position of the air bag, the direction where the air bag unfolds and expanses may vary depending on the manner in which the air bag is folded, and a stable expansion of the air bag in a desired direction cannot always be obtained. Note that a bent position is referred to as a position where the air bag gets twisted or bent due to a difference in pressure caused by difference in passage distance of inflation gas or a cell shape (formed by stitching).
In another conventional air bag system A, as disclosed in JP 2006-88846 A, pushed load is applied onto a cover 310 housing a rolled air bag 330 when the cover 310 is installed to a roof side rail 300, whereby the cover 310 deforms to be flat, which causes a pushing stroke loss or pushed load loss. Further, the conventional air bag A has another disadvantage that the rolled air bag 330 hinders an operator from checking the position of the clip 360 relative to a lock hole 300a of the roof side rail 300.
The present invention has an object to provide an air bag system that has an reliable expansion property of an air bag even if a cover is formed to be bent in order to go along a face shape of a vehicle body where the cover is installed, and that facilitates installation to a vehicle body.